Since servo positioners are used for precise controlling of such equipment, for example, as variable pitch propellers for marine equipment, engine governors, steering mechanisms, steam valves, throttles, or for positioning potentiometers, butterfly valves, hopper gates, torque converters, or hydrostatic transmissions, it is important that the servo positioner be positive in its action, quick to respond to a control impulse, and be positionally stable and free of hysteresis.